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220 Cards in this Set

  • Front
  • Back
retrograde orbit moon. axis of rotation = 157 degrees with respect to its planet's axis. Hence, one side always faces the planet
triton
7th largest moon & 16th largest object in the solar system. Larger than Pluto and and Eris.
triton
Its plains are dotted with pits, such as the Leviathan Patera, probably vents from which lava emerged. There are four flat plains, they are dotted with black points, maculae.
triton
contains a large series of fissures and depressions, known as "cantoloupe's terrain." the theory for its formation is diapirism, the rising of lumps of less dense materiel through a stratum of denser material, couuld also be cryovolcanism.
triton
Phoebe and Triton were thought to have originated from this region.
kuiper belt
first evidence for it was found in 1992. the first astronomer to suggeest its existence was frederick c. leonard.
kuiper belt
kenneth edgeworth hypothesized that the material within the primordial solar nebla was too widely spaced to turn into planets, so it turned into a bunch fo random objects.
kuiper
stretches from 30 AU to 55 Au. the classical part extends from 42-48, which comprises 2/3 of th ematerial. They are referred to as cubewanos.
kuiper belt
it has a cliff - berstein and trilling found evidence that its rapid decline in objects of 10 km or more is real. Explanations include that the material is too scarce at that distance to form large objects.
kuiper belt
studies indicate that it is composed of light hydrocarbon, ammonia and water ice, in common with comets. Roughtly the upper limit of the mass is estimated to be 1/10 of the mass of earth.
kuiper belt.
Neptune's influence is to weak to explain how the objects don't accrete and such massive vacuuming, though the Nice model proposes that it could have been the cause of mass removal of the past.
kuiper belt
It includes objects such as centaurs. Of the four largest TNO's, three (Eris, Pluto, Haumea) possess satellites. There are a lot of binaries.
Kuiper Belt
First spacecraft to explore it was New Horizons, headed by Alan Stern of Southwest Research Institute.
kuiper belt
he discovered two natural satellites in the solar system, namely Uranus's Miranda and Neptune's Nereid. He discovered carbon dioxide in Mars.
kuiper
spent most of his time at the University of Chicago, and he helped identify landing sites on the moon. He was awarded the Janssen Medal of the Astronomical Society of France. He received the Henry Norris russell Lectureship and received the Kepler Gold Medal
kuiper
3rd largest, and fourth most massive planet, discovered by William Herschel in 1781.
uranus
it has the coldest planetary atmosphere , 49 K. It has an axis of rortation tilted nearly sideways. 1986 Voyager 2 showed it as virtually featureless.
uranus
earliest record of it was 1690 when John Flamsteed observed it 6 times, cataloging it as 34 Tauri. Pierre Lemonnier observed it between 1750 and 1769.
uranus
discoverer initially thought it was a comet, and he named it George's Star. Jerome Lalande proposed to name it after the discoverer, however they settled on its current name.
uranus
revolved every 84 years, and the average distance is roughly 20 AU from the sun. discrepancies were found in its orbit, and John Couch Adams proposed the differences must be due to an unseen planet. Le Verrier started to research, and then Galle located the new planet.
uranus
because of tilt, the top gets more sunlight then the middle, but it is still hottter at the equator. It is theorized that this tilt is due to a collision with an earth-sized figure.
uranus
It is not understood why it has a low thermal flux. It radiates hardly any excess heat. this was thought to be because of its tilt, and the impact of a collision which depleted its temperature.
uranus
It was discovered to have rings second. It has 13 identified rings - recently it was found to have unknown rings, twice the distance from the planet as the previous rings. This recent discovery also spotted two small satellites, one (Mab) shares its orbit with the new ring.
uranus
known to have 27 satellites. Its moons are named after the works of shakespeare and Pope. Its satellites system is the least massive among the gas giants.
uranus
five main satellites = miranda, ariel, umbriel, titania, and oberon. Titania = 8th largest moon in the solar system. Lassell discovered Ariel and Umbriel. Kuiper found Miranda. The rest were found during the Voyager 2 fly-by.
uranus
inner moons include Mab and cupid. Peridta was retroactively discovered in 1999. Margaret was recently found in 2008. Two innermost moons = cordelia and Ophelia. Puck is the largest of inner moons.
uranus
9 irregular moons - Sycorax, and Trinculo. [also includes Prospero, Setebos, and Ferdinand.] The inclinations between 60 and 140 are devoid of moons due to the kozai instability.
uranus
Along with discovering a lot of planetary stuff, he composed 24 symphonies.
herschel
he was born in hanover. He joinedthe Hannoverian Guards. He played the cello along with the obe and the Organ.
herschel
he worked with his sister Caroline, in 1783 giving her a satellite. He discovered 4 moons (Oberon, Titania, Enceladus, Mimas).
herschel
He created an extensive catalogue of nebulae, and he discovered that oduble stars aren't optical doubles but true binary stars, proving Newton's Laws of Gravitation apply outside the solar system.
herschel
he found that he solar system is moving through space and found the ice caps on Mars.
herschel
he coined the word "asteroid" meaning star-like. he used a microscope that coral had the characteristic thin cell walls of an animal, instead of being a plant.
herschel
discovered heliocentric theory.
copernicus
His professor was Albert Brudzewski. His library was later carried off as war booty by the Swedes during the Deluge.
copernicus
he wrote a study on the value of money (monetae cudendae ratio) formulated Gresham's Law 70 years before Gresham. He also formulated the quantity theory of money.
copernicus
Bernard wapowski told someone to publsh an enclosed almanac written by him. It mentions his theories about the earth.
copernicus
after the death of the prince-bishop of Warmia Mauritius Ferber, he participated in the election of his successor Johannes Dantiscus.
copernicus
he was slightly a physician. eight years after his death, Erasmus Rehinhold would publish the Prutenic Tables, tables based on his work.
copernicus
He presented his major theory in his "little commentary." Georg Rheticus became his pupil, and wrote a book under him (Narratio Prima) and later published a treatise on trigonometry by him.
copernicus
bartolomeo Spina wanted to condemn his major work. he first recorded stellar observations with an eclipse of Aldebaran. he discussed astronomy with Clement VII.
copernicus
its surface is composed of basalt and iron(III) oxide.
mars
its history can be split up into three main epochs (Noachian - formation of the oldest extant surfaces 3.7 billion years ago. The Tharsis bulge volcano upland formed then).

Hesperian 3.5 B to 1.8 B - marked by the formation of extensive lava plains

Amazonian Epoch (1.8 B to now) - Olympus Mons was formed
mars
its soil is composed of salt perchlorate - which means it is considerably basic - measuring at 8.3.
mars
water was thought to have occurred during when the valles marineris formed early in Mars's history, forming massive outflow channels. A smaller but more recent outflow may have occurred when the Cerberus fossase chasm opened 5 million years ago, making frozen ice stilll visible on the Elysium Planitia.
mars
Johann Heinrich Madler and Wilheim Beer (along with mapping the moon) established most of its surface and determined its rotation period.
mars
Mariner 9 provided extensive imagery of it in 1972.
mars
it is thought to have an impact crater the size of europe & Asia & Australia, surpassing the South Pole - Aitken basin as the largest impact crater.
mars
the largest known mountain in the solar system
olympus mons
located in upland Tharsis, it is three times the size of Mount Everest
olympus mons
valles marineris (known as Agathadaemon) is its largest canyon (equivalent to the length of europe).
mars
lost its magnetosphere 4 B years ago. Its atmosphere is 95% CO2, 3% Nitrogen, 1.6% argon.
mars
missions to it include Mariner 4, Mariner 9 - the successful objects to land on it were the Soviet [planet[ 2 and 3]. Viking 1 and 2 also landed on it successfully. The most recent mission was Phoenix.
Mars
In 2003, NASA launched Spirit and Opportunity to go here.
Mars
larger and closer of two moons of mars
phobos
discovered by Asaph hall
Phobos and Deimos
most prominent crater = stickney crater, named after the discoverer's wife. the kaidun metereorite is thought to be a pieceo f this.
phobos
it moves around its planet faster than the planet rotates, therefore it rises in the west and moves to the east - circling twice every day.
phobos
because of its orbital period being so short, tidal deceleration is decreasing its orbital radius at the rate of 20 meters / century. In 11 million years it should either hit the planet, or turn into a ring. It is a Mohr-Coulomb body.
phobos
it is estimated it will pass the roche limit for a rubble pile when its orbital radius drops more.
phobos
there are speculations that it could be hollow. Iosif Samuilovich Shklovsky suggested it was a thin sheet metal. Fred Singer, science advisor to Eisenhower, supported this theory.
phobos
PRIME wanted to land on it. The proposed landing site is the namesake "monolith".
phobos
its features are named after astronomers who studied it and places from Swift's Gullivers Travelers. The only named ridge is the Kepler Dorsum.
phobos
smaller and outer of mars's moons
deimos
The two largest craters are Swift and Voltaire (3 km across)
deimos
unlike corresponding moon, it rises in the east and sets in the west.
deimos
distance within which a celestial body, held together by its own gravity, will disintegrate due to tidal forces and the body's gravitational self-attraction.
roche limit
depends on the rigidy of the satellite - it will maintain its shafe until tidal forces break it apart. It can also be a fluid satellite.
roche limit
can be derived using kepler's 3rd law + newton's law of universal gravitation. It takes into account the force of gravitation, the centrifugal force, and the self-gravitation field of the satellite.
roche limit
limits the mass of bodies made from electron-degenerate matter, a dense form of matter which consists of nuclei immersed in a gas of electrons.
chandrasekhar limit.
no rotating white dwarf can be heavier than this
chandrasekhar limit
happens because the energy of electrons increase because of compression since they can't operate within the same state (Pauli) - hence, pressure is exerted on the electron gas.
chandrasekhar limit
Lieb and yau gave a derivation of it from the schrordinger wave equation.
chandrasekhar limit
Ralph H. Fowler observed the relationship between density, energy and temperature of white dwarves. This Fermi gas model was used by E.C. Stoner to calculat ethe relationship - Wilheim Anderson corrected this model. Then Frenkel worked on it, but it was ignored. THen its namesake worked on it - solving the hydrostatic equation. It was also calculated by Lev Davidovich Landau.
chandrasekhar limit
its opposition was arthur stanley eddington, he thought that something would stop the collapse. Although Bohr, Fowler, Pauli and others agreed with his anaysis, due to Eddington, they didn't publicly support the namesake.
chandrasekar limit
the champagne supernova, seen by David Branch, was spinning so fast the centrifugal force exceeded this, causing it to cause a massive explosion.
chandrasekhar limit
group of astronomical objects listed by the name sake in his Catalogue of Nebulae and Star Clusters.
Messier
The original motivation was that the namesake was a comet hunter, but he was frustrated by objects that weren't comets, but resembled them. In collaboration with his assistant Pierre Mechain he put together a list.
messier
it first contained 103 objects ; the first edition covered 45 objects. The first addition came from camille Flammarion, who added 104. Helen Sawyer Hogg added 105-107. Owen Gingrich and Jones added a few more.
Messier
In the constellation Taurus - is currently expanding at about 1500 km / s
Crab Nebula
First observed by John Bevis in 1731 and corresponds to a bright supernova recorded by the Chinese and Arabs in 1054.
Crab Nebula
Named because of the Earl of Rosse who observed it at Birr Castle and referred to it by the drawing he made.
Crab Nebula
Iosif Shklovsky proposed that its blue region was dominated by synchroton radiation, which is given off by the curving of electrons at the speed of light.
crab nebula
there are two faint stars at the center. It was identified when Rudolf Minkowski found the spectrum to be extremely unusual.
crab nebula
it is weird that the combined mass of it + its pulsar don't add up to the progenitor star. The missing mass is thought to be between 1-5 solar masses. The main theory to solve this is a substantial portion of the mass was carried away by a stellar wind.
crab nebula
X-ray emissions were used to track its transity, but didn't work too well. The moon's transit helped to directly identify where it was. Every june, the sun's corona passes in transit , and variations in its radio waves can show its density. In 1296 and 2003 Saturn transited it ; Titan also had a transity - which showed Titan's atmosphere to be 880 km.
crab nebula
Originally thought to be orbiting the Milky way Galaxy, these are two irregular dwarf galaxies.
Large and Small Magellanic Clouds
Were seen by Al Sufi in 964 who, in his Book of Fixed Stars, called it the "White Ox". In Europe, it was observed by Peter Martyr and Andreas Corsali - then by Antonio Pigafetta.
Magellanic clouds
Roughtly 21 degrees apart and 75,000 light years away from one another. Until the discovery of the Sagittarius dwarf elliptical galaxy in 1994, they were the closest galaxies
magellanic clouds
The first systematic observations were carried out by Edmund Halley on the island of St. Helena. One is in the constellation Dorado, while the other is in Tucana.
Magellanic Clouds
The distance was estimated by Henrietta Levitt using Cepheid variable stars.
Magellanic Clouds
class of pulsating variable stars. The relationship between their luminosity and pulsation is precise. They are the foundation of the extragalactic distance scale.
cepheid variable stars.
brightest star in orion
rigel
sixth brightest in the sky
rigel
it is a blue supergiant star - between 700-900 light years away. 17 solar masses, shining with 40,000 times the luminosity of the sun. The nearest powerful star is Naos (in Puppis)
rigel
It lights up the witch head nebula. it is surrounded by a shell of expelled gas, perhaps by its pulsations, or stellar winds. it's not settled.
rigel
It has been known as a visual binary since 1831, when it was measured by F G W Struve. Its B star is separated by 2200 AU. They orbit one another every 9.8 days.
Rigel
Its name comes from its location at the "left foot" of Orion. It has other names like Algebar. In Chinese it is known as the "seventh of the three stars"
rigel
It is found below and to the ight of Mintaka, Alnilam, and Alnitak - which are in the same constellation.
rigel
second brightest star in Orion and the ninth brightest in the night sky
betelgeuse
it is a vertex of the winter triangle and center of the winter hexagon. It is a red supergiant, and one of the most luminous stars known.
betelgeuse
its angular diameter was first measured by michelson and Pease using the John D. Hooker interferometer atop Mount Wilson
betelgeuse
Theorized to have a name meaning "the hand of al-jauza" - it was at one time thought to be the "armpit of orion". In chinese astronomy it was thought to be the fourth star of the constellation.
betelgeuse
Its variability of brightness was first described by JohnHerschel in 1836, when published in his Outlines of Astronomy.
betelgeuse
it has the third largest angular diameter. It was the first to be measured with an astronomical interferometer. Direct parallax measures from space say its 495 light years away., while radio emissions give 640 light years.
betelgeuse
it is thought to become a supernova, outshining the moon in the night sky. Nobel Laureate Charles Townes announced that 15 years of UC Berkeley's Infrared Spatial Interferometer atop Mt. Wilson in Southern California said it has decreased 15 A% in the last 20 years.
betelgeuse
Brightest star in the night sky - twice as bright as canopus, the next brightest star.
sirius
known as the "dog star"
sirius
it was the first star to have its velocity measured. Sir William Huggins examined the spectrum of the star with a red shift.
sirius
frederich bessel deduced from changes in its motion that it had an unseen campaign. Soon, American Alvan Graham Clark found its companion, called "the Pup"
sirius
In 1915, Walter Sydney Adams, using a 60-inch reflecter at Mount Wilson Observatory observed its spectrum and determined it was a faint whitish star. Its diameter was first measured by Robert Hanbury Brown and RIchard Q. Twiss at Jodrell Bank.
sirius
these three form the winter triangle
procyon, betelgeuse, sirius
It was thought to maybe be a part of the Ursa Major Moving Group. But instead is thought to be a member of its namesake supercluster.
sirius
scatter graph of stars showing relationship between stars' absoltue magnitudes or lumonisity versus their spectral types or classifications.
HR diagram
the original type originally displayed the spectral type of stars on the horizontal and the absolute magnitde on the vertical axis.
HR diagram
most of its entries are on the main sequence. There is also a namesake gap between A5 and G0.
HR diagram
can be used to calculate how far a star cluster is from earth.
H-R Diagram
charged particles around Earth held in place by the magnetic field.
Van Allen radiation belt
It has a cavity, called the Chapman Ferraro Cavity, where it resides and splits into two.
van Allen belts
Was confirmed by Explorer I and Explorer III. Its closes approach to the surface is at the South Atlantic Anomaly.
Van Allen Belts
it is the product of the decay of albedo neutrons, as a result of the decay of albedo neutrons which are themselves the result of cosmic ray collisions in the upper atmosphere.
vann allen belts
its Ultra Deep Field Image is the msot detailed image ever.
hubble telescope
5 servicing missions, occurring in may 2009 - when its imaging flaw was corrected.
hubble telescope
the latest servicing should allow it to function until 2014, when its successor the James Webb Space telescope will be launched.
hubble telescope
Lyman Spitzer recommended in "Astronomical advantages of an extraterrestrial observatory" that we need a telescope in outer space. In 1965, he was put at the head of the project.
hubble telescope
Work on the project had been given to the Marshall Space Flight Center - which was given the responsibility for design, development, and construction.
hubble telescope
It is a Cassegrain reflector of Ritchley - Chretien design - it has two hyperbolic mirrors. Perkin Elmer intended to use a computer machine - but they ended up using Kodak. The Itek mirror is at the Magdalena Ridge Observatory
hubble telescope
Initially it held 5 scientific instruments, the Wide Field and Planetary camera, Goddard High resolution Spectrograph, High Speed Photomoter, Faint Object Camera and the Faint Object Spectrograph.
hubble telescope
Within a week, the images showed there was a serious problem with the optical system. the primary mirror had been in the wrong shape ; the prescribed curve of 10 nanometers. Lew Allen, director of the Jet Propulsion Laboratory was to determine how the error happened.
hubble telescope
COSTAR was to fix the spherical aberration (Corrective Optics Space Telescope Axial Replacement) - Riccardo Giacconi announced that he would allow amateur astronomers to use it.
hubble telescope
Born in Marshfield, Missouri. He worked at Mount Wilson Observatory near Pasadena California.
hubble
Using the Hooker Telescope, he identified Cepheid variable Stars in several spiral nebulae - including the Andromeda Nebula.
hubble
he discovered the redshift of galaxies, although it was understood by Keeler, Slipher, and campbell at other observatories. Comparing his measurements with Leavitt's period-luminosity relationship, he and Milton L. Humason discovered a proportionality with redshift
hubble
He and Humason formulated the empirical redshift distance law, termed his namesaw law. this equation is consisten with einstein's equations of general relativity for a homogenous, isotropic expanding space.
hubble
He used a system for classifying galaxies based on his "tuning-fork" diagram.
hubble
describes that various galaxies are receding from the earth is proportional to the distance from us.
hubble's law
the recession velocity was based on redshifts, many measured much earlier by Vesto Slipher.
hubble's law
Alexander Friedmann derived his Friedmann equations from Einstein's field equations showing that the universe might expand at a rate calculable by the equations - known as the scale factor. Georges Lemaitre found the same solution.
hubble's law
explained by the doppler effect, it's constant was published by Allan Sandage - but it would be a while before ocnsensus.
hubble's law
The Big Bang Interpretation of this is known as Olber's Paradox. If the universe of was infinite, static, and filled with stars, then every line of sight would be a star - and thus the sky would have the sight of a star - the solution is that light has yet to reach us.
olber's paradox
it is measured by the redshift of distant galaxies and determining the distances at the same time. It was debated between Gerard de Vaucouleurs - who claimed it was 100, while Sandage claimed it was 50.
hubble's constant.
the ACDM model of high redshift using the SUnyaev- Zel'dovich effect and optical surveys give it a value of 70
hubble's constant
its reciprical is proportional to time since the Big Bang - and it is required by isotropy and universal homogeneity
hubble's constant
Georges Lemaitre proposed it - although he called it "hypothesis of the primeval atom".
big bang
it relies on einstein's general relativity with simplifying assumptions, such as homogeneity and isotropy of space. The governing equations were formulated by Friedmann.
big bang
Fred Hoyle coined this term, during a 1949 radio broadcast. Hoyle liked the "steady state" cosmological model and wanted this to be offensive.
big bang
it developed from observations from many. Slipher measured the first doppler shift of a "spiral nebula." Ten years later, Friedmann derived his equations. Lemaitre then predicted the recession was due to expansion of the universe
big bang
Ideas to explain Hubble's observations to not support this included Milne Models, the oscillatory Universe and Fritz Zwicky's tired light hypothesis.
big bang
It was developed by George Gamow, who introduced its namesake nucleosynthesis) - and his associates Alpher and Herman who predicted CMB.
big bang
at a finite time in the past, there existed an infinite density and infinite temperature, which broke down relativity, which can't be earlier than the Planck epoch.
big bang
depends on two assumptions, the universality of physical laws, and the cosmological principle - which states the universe if homogenous and isotropic.
big bang
as the universe expanded, it cooled to where photons could no longer be created nor destroyed - but still high enough for electrons and nuclei to remain unbound. photons were continually reflected from these free electrons through thomson scattering -thus rendering the universe opaque.
big bang?
Arno Penzias and Robert wilson discovered this at Bell Laboratories.
CMB
kepler's laws
1) orbit is an ellipse
2)line joining planet and sun sweeps out equal areas during equal intervals
3) the square of the orbital period is directly proportional to the cube of the semi-major axis of its orbit
also a statement of the conservation of angular momentum
kepler 2
1976 - orbiting and landing on mars
Viking
1979-1980 - flybys of jupiter and saturn
voyager I
flybys of uranus and neptune
voyager II
19990 - orbited venus sending back detailed radar maps of its surface
magellan
1995 - closeup study of jupiter and its moons
galileo
1997 - orbits mars sending back detailed image of surface.
magellan
2004 - closeup study of saturn and its moons and rings - will land a probe on titan
Cassini
has been observed since 240 BC - but its orbit was computed by its namesake. it last appeared in 1986 0 and will reappear in 2061.
halley's comet
In his Synopsis of the Astronomy of Comets - he used Newton's laws to calculate the gravitiational effects of Jupiter and Saturn on cometary orbits.
halley
its prediction was correct, seen on dec 25, 1758 by johann Georg Palitzch.
halley's comet
hypothesized spherical cloud of comets roughtly 50,000 AU from the sun. It is close to Proxima Centauri. It defines the gravitational boundary of our solar system.
oort cloud
It is thought to have two separate regions, a spherical outer namesake and a inner one, the Hills Cloud
Oort CLoud
Estonian Ernst Opik postulated thsi initially. It was suggested by its namesake.
oort cloud
its total mass is thought to be 5 times the earth's mass. its mass was thought to peak 800 million years ago after formation.
oort cloud
models by julio Angel Fernandez suggest that its scattered disk formation is the source of periodic comets. Its namesake saw "cometary fading."
oort cloud
Four objects are thought to belong to it so far - Sedna, Cr105, SQ372, KV42.
oort cloud
most luminous electromagnetic events in the universe. THey can last from illiseconds to an hour - although most last a few seconds - they usually have after - glows.
GRBs
First detected by Vela Satellites - initially they were thought to be collisions between comets and neutron stars. The team at Los Alamos Scientific Laboratory, led by Klebesadel, filed away the datae for investigation.
GRBs
BeppoSax detected one of these when its X-ray amera was pointed towards its direction. The second one placed it, through redshift, roughly 6 billion light years away. Swift was sent up to detect these.
GRBs
these are the systems that produce GRBs
progenitors
the most widely accepted model for these is the collapsar model. It is thought tto be a a massive, low metallicity, rapidly rotating star collapses into a black hole and swirls into an accretion disk. This drives jets towards the rotational axis, which are sometimes replaced with a magnetar.
GRBs
the closes galactic analogs of thes stars that produce these are Wolf-Rayet stars.
GRBs
small star composed mostly of electron-degenerate matter - they are very dense - comparable to the mass of the sun and the volume the earth.
white dwarves
They were recognized by Henry Norris Russell, Edward Charles Pickering and FLeming - it was coined by Willem Luyten in 1922
white dwarves
they are thought to be 6% of the stars in our neighborhood - while 97% of stars in our galaxy.
white dwarves
it is only supported by electron degeneracy pressure - the chandrasekhar limit applies to it. A carbon-oxygen one that approaches it can explode as a supernova via carbon detonation.
white warf
It was first discovered in the star system of 40 Eridani - the pair Eridani B/C was discvoered by Friedrich Wilhelm Herschel and then observed by Wilhelm Struve.
white dwarves
the majority lie between .5 to .7 solar masses. They don't consist of atoms with chemical bonds, but rather plasma of unbound nuclei and electrons.
white dwarves
G.P. kuiper was the first to try to classify their spectra. It was initially scaled by Edward M. Sion.
white dwarves
bottom left of HR diagram
white dwarves
their magnetic fields were predicted by P.M.S. Blackett. He thought that they should generate a magnetic field proportional to their angular momentum [blackett effect].
white dwarves
was first used in 1926 and coined by Swiss astrophysicist Fritz Zwicky
supernova
The first one was observed by Chinese astronomers in 185 AD. In the 60's - they suggested that the universe was expanded.
supernova
very energetic and distant galaxy with an active galactic nucleus. They were first identified as being high redshift sources of electromagnetic energy, including radio waves and visible lights.
quasars
they are the most luminous objects, usually tend to be 3 billion light years away. the brightest on is in Virgo.
quasars
they were discovered by Maarten Schmidt in 1967 and were good evidence against Fred Hoyle's Steady State cosmology.
quasars
have the same properties as galaxies, but are for more powerful. a minority of them show radio emission which originate as jets moving at the speed of light - appearing as a blazar.
quasars
the oldest ones, display a Gunn-Peterson trough and have absorption regions in front of them indicating that the intergalactic medium was neutral gas. More recents ones show no absorption regions but rather spiky areas known as Lyman - alpha forests.
quasars
They were first discovered with the lovell telescope as an interferometer. Hundreds of them were cataloguedi nt he Third Cambridge Catalogue. in 1962, one was hown to go through five occultations of the moon, measurements were taken by Cyril Hazard and John Bolton using hte Parkes Radio telescope and allowed maarten schmidt to identify them.
quasars
the term was coined by Chinese Hong-Yee Chiu.
quasars
it was a topic of debate in the 60's whether they are near or far - it was suggested that they were due to light escaping a deep gravitational well. however the stars int hem to form such a well would be unstable in excess of the Hayashi limit. They also show unusual spectral emissions.
quasars
class of galaxies with nuclei that produce spectral line emissions from highly ionized gas - named after the astronomer who identified them in 1943. They contain supermassive black holes
seyfert galaxies
states that the total energy radiated per unit surface area of a black body in unit time is directly proportional to the fourth power of the black body's thermodynamic temperature
stefan-boltzmann law
it is a certain quantitiy that if containing a sufficient amount of mass (and density) the force of gravity is so great that no known force or degeneracy pressure could stop it from collapsing it into a gravitational singularity.
schwarzschild radius
its namesake found an exact solution to einstein's field equations to find this quantity. it is proportional mass - for the sun it is 3 km - while the earth is 9 mm.
scwarzchild radius
the significance of this at r = 2M was first raised by Jacques Hadamard who asked what would happen if this occurred - einstein said it couldn't because it would destroy the universe, and called it the "Hadamard disaster"
singularity
an original assumption of this assumed it was an incompressible fluid. einstein argued that this could never happen. That same year, Robert Oppenheimer and Hartland Snyder considered a model of a dust lcoud and showed it could reach singularity.
schwarzchild radius
r = 2Gm / c2
schwarzchild radius
Its brightest star is Spica. A noted galaxy that is not part of it is the Sombrero Galaxy.
virgo
M31 - features include the brightest star - Alpheratz / Sirrah). It contains M33 - the Triangulum Galaxy.
andromeda
latin for cup-bearer - it contains the first planetary system found around a red dwarf. - it contains M2, M72, M73. Two well known nebula in it are The Saturn Nebula and the Helix Nebula
Aquarius
Latin for Ram - Its brightest star is Alpha Arietis - It includes galaxies like NGC 697, 772, ....
aries
latin for crab. It contains 55 Cancri - a quintuple planet system. It is the home of Praesepe (M44, big star) - also the Beehive Cluster or the Gat eof Men.
cancer
latin for greater dog. Contains Adhara (the Virgins), Wezen (the weight), Aludra, Furud, Muliphen. The only messier object is M41, 4 degrees below Sirius - its brightest star.
canis major
Latin for smaller dog - contains only two bright stars - Procyon and Gomeisa.
canis minor
Represents the vain queen who boasted about her beauty. Looks like a W or M - contains two stars - p Cas and V509 Cas. It contains M52 and M102. It contains Tycho's star.
cassiopeia
latin for twins. It is associated with castor and pollux. It contains the Eskimo Nebula. It also has the Medua nebula.
gemini
latin for lion. Bright stars - Regulus - Denebola. Part of its makes up the asterism known as the sickle. Wolf 359 is in it. It contains a namesake triplet and namesake ring.
leo
known as the "hunter' - largest constellation - it includes a prominent belt. Its stars include Betelgeuse, Rigel, Bellatrix, Mintaka, Alnilam, Alnitak, and Saiph. It contains the Trapezium and the namesake nebula. Another famous object is the Horsehead Nebula. It also contains Barnard's Loop and the Flame Nebula.
Orion
Named for a Greek hero, its brightest and most brilliant star is Mirfak (Algenib). It also contains Algol - which is its most famous star.
Perseus
latin name is plural fish. Its brightest star is Van Maanen's Star - also containing one galaxy, M34. It contains the Testudo (turtle)
Pisces
latin for the archer - it has an asterism known as the Teapot. One of its brightest = Rukbat. It contains the most stars with planets - 16 have them. It contains the Lagoon Nebula, the Omega nebula (Horshoe nebula), the Trifid Nebula.
sagittarius
latin for scorpion. Some of its bright stars include Antares. It contains the Butterfly Cluster and the Ptolemy Cluster
Scorpius
Latin for bull. The outline of a V or A shaped asterism of stars is a prominent member of the Hyades, the nearest distinct open star cluster. In the northeastern quadrant lie the Pleisades.
taurus
third brightest in Orion, 27th overall. Known as female warrior.
Bellatrix